Word for "making something more tolerable?"

I think sweeten may suggest the idea of making life more acceptable and enjoyable with pleasant things like art and entertainment:

• To make more pleasant

Source: www.thefreedictionary.com

From thefreedictionary...

alleviate
to make (pain, sorrow, etc) easier to bear; lessen; relieve

ameliorate
to make or become better or more satisfactory; improve; meliorate.

Usage: Ameliorate is often wrongly used where alleviate is meant. Ameliorate is properly used to mean "improve", not "make easier to bear", so one should talk about alleviating pain or hardship, not ameliorating it.

So OP must decide whether he thinks life is "okay, but could be better" (use ameliorate), or "almost unendurably harsh" (use alleviate).